The investigation into the deadly explosion at Hanwha Chemical Corp. is pointing to long-established negligence and lax safety management as the cause of the deadly accident.

Since the explosion took the lives of six workers of the Hanwha subcontractor -- Hyundai Environment -- on July 3, the authorities have been probing into the accident. 

A number of officials from both companies including the chiefs of Hyundai Environment and Hanwha Chemical’s safety team are under suspicion of being responsible for the fatal explosion.

The blast occurred during welding work on a storage tank to expand a wastewater disposal facility at its plant in Ulsan. At the time of the accident, the wastewater treatment facility was thought to have had a buildup of toxic and inflammable gases.

As the authorities question Hanwha and Hyundai Environment officials, it has been revealed that Hyundai Environment lacked qualified personnel on staff. Under local regulations, companies offering construction services for environmental facilities require at least two personnel with state-approved qualifications in water quality management, and two qualified in construction and chemical engineering fields.

The contractor is also reported to have used part-time workers and unqualified laborers as safety observers.

As for the chemicals arm of Hanwha Group, it has been revealed that the company did little to verify the qualifications in selecting the contractor.

Although Hanwha had initially claimed that the contractor selection was not based solely on the lowest bid, police investigation has since revealed that the company made the selection having only reviewed the documents submitted by the contractor. It was also revealed on Monday that the facility that exploded had not been subjected to state inspection for 19 years.

As the investigation continues, the state-run Korea Occupational Safety and Health Agency has been selected to lead the comprehensive safety, health and management audit on Hanwha’s Ulsan plant.

By Suk Gee-hyun (monicasuk@heraldcorp.com)